Evolution, American-Style

“Evolution, American-Style” by Mike Licht, NotionsCapital.com.

Researchers at the Safe Transportation Education and Research Center at the University of California, Berkeley, have found that obese drivers are more likely to die in vehicle crashes than non-obese people in the same auto accidents, according to Emergency Medicine Journal (EMJ). The researchers, Thomas M. Rice and Motao Zhu, conducted the study because few other studies have looked at how obesity affects injury outcomes in traffic collisions, an EMJ abstract says.

As Nicholas Bakalar reports for The New York Times blog Safe Travels, to arrive at their conclusions, Rice and Zhu reviewed data on auto accidents recorded in the Fatality Analysis Reporting System, managed by the National Highway Traffic Safety Administration. The data covered road accidents in the U.S. from 1996 to 2008, and the study used the World Health Organization definition of obese, Cathy Payne writes for USA TODAY.

From data on 41,283 collisions, the researchers selected accidents in which the cars, trucks, or minivans were the same size, and categorized drivers of the wrecked vehicles into four groups based on body mass index (BMI), Bakalar writes.

Bakalar goes on to say:

In the analysis, there were 6,806 drivers involved in 3,403 accidents, all of which involved at least one fatality. Among the 5,225 drivers for whom the researchers had complete information, 3 percent were underweight (a B.M.I of less than 18.5), 46 percent were of normal weight (18.5 to 24.9), 33 percent were overweight (25 to 29.9) and 18 percent were obese (a B.M.I. above 30).

Although the death rates among drivers who were of normal weight, lower weight, and overweight were the same, among the obese drivers, the higher the BMI, the more likely a driver was to die in an accident, Bakalar writes. He reports: “The reasons for the association are unclear, but they probably involve both vehicle design and the poorer health of obese people.”

Payne writes that the study’s authors cite previous research that showed that an obese driver’s lower body is propelled further on impact before the seat belt can engage the person’s pelvis, while the upper body is held back, and that this is because the obese person’s extra girth prevents the seat belt from fitting well. Payne quotes Keshia Pollack, associate professor with the Center for Injury Research and Policy at the Johns Hopkins Bloomberg School of Public Health in Baltimore, who said research shows that obese people, especially morbidly obese ones, are less likely to wear seat belts or to use them properly.

But Balakar notes that other factors that might have affected fatality rates — including seat belt use, air bag deployment, alcohol use, vehicle type, the age and sex of the driver, and whether or not the collision was head-on — did not explain the study’s conclusion.

Bakalar quotes Dr. Rice:

‘Vehicle designers are teaching to the test — designing so that crash-test dummies do well,’ Dr. Rice said. ‘But crash-test dummies are typically normal size adults and children. They’re not designed to account for our nation’s changing body types.’

Payne notes that according to the Centers for Disease Control and Prevention, one-third of U.S. adults (35.7%) are obese. Colorado ranks first in the nation for having the lowest adult obesity rate (20.7%), according to several reports, as L. Wayne Hicks reported last August in the Denver Business Journal.

The states with the highest obesity rates are: Mississippi (the highest at 34.9%), Lousiana, West Virginia, Alabama, Michigan, Oklahoma, Arkansas, Indiana and South Carolina (tied at 30.8%), and Kentucky and Texas (tied at 30.4%), according to a press release by Trust for America’s Health (TAH). TAH is a nonprofit, non-partisan organization dedicated to saving lives by protecting the health of every community, and working to make disease prevention a national priority. Its statement warns that adult obesity rates could exceed 60% in 13 states by 2030.

Image by Mike Licht, NotionsCapital.com.

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